A gas turbine engine generally includes a fan and a core arranged in flow communication with one another. Additionally, the core of the gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In operation, an airflow is provided from the fan to an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section to the turbine section. The flow of combustion gasses through the combustion section drives the combustion section and is then routed through the exhaust section, e.g., to atmosphere. In particular configurations, the turbine section is mechanically coupled to the compressor section by one or more shafts extending along an axial direction of the gas turbine engine.
Additionally, for at least some gas turbine engines, the fan is a variable pitch fan including a plurality of fan blades. Each of the fan blades may be rotatably attached to a disk about respective pitch axes, and the disk may be rotatable about a central axis by the one or more shafts of the core. For example, each fan blade can be attached to a trunnion mechanism which extends through an individual disk segment of the disk. The trunnion mechanism can, in turn, be retained within a respective disk segment by a keyed connection. For example, the trunnion mechanism may define a key slot and the disk segment may include a support surface. A key positioned in the key slot interacts with the key slot and the support surface to retain the trunnion mechanism within the respective disk segments.
However, the keyed connection may be required to withstand substantially all of the centrifugal forces on the fan blade during operation of the fan—the centrifugal forces acting in a direction parallel to the pitch axis. Accordingly, the keyed connections must be made relatively large and robust to support such forces. Thus, a keyed connection for a variable pitch fan blade capable of reducing ineffective force on the keyed connection would be useful.